Screw threading machine



Sept. 30,1941. w. WIIEMHONERV AL 2,257,253

SCREW THREADING MACHINE Filed June 20, 1958 2 Sheets-Sheet l WWW mvmaqAllomey Patented Sept. 30, 1941 SCREW THREADING MAC 1 Wilhelm Wemhiinerand Werner Piage, Berlin, Gey

Application June 20, 1938, Serial No. 214,733 In Germany June 19, 193?(Granted under the provisions of sec. 14;, act of March 2, 1927; as: o.s. 5)

12 Claims.

Our invention relates to improvements in screw threading machines, andmore particularly in machines of the type comprising a pair ofexternally screw threaded rolie'r dies placed one be side the other andadapted to be.rotated in the same direction for rolling a screw threadinto a blank placed between the same. One of the ob- Jects of theimprovements is to provide a machine of this type, in which means areprovided.

in addition to the said roller dies. for holding the blank being rolledin position. With this object in view our invention consists in providing a support between the said roller diesspaced from the plane passingthrough the axes of said roller dies so far that. the blank is held inposition with its axis in or near the said plane. In the preferredconstruction the said support is located so that the axis of the blankis located slightly below the said plane. We have found that thisconstruction is preferable because thereby it is impossible that theblank being rolled be ejected from between the roller dies by thecircumferential forces transmitted thereto by the roller dies.

Our invention also relates to the manner of mounting the roller dies onthe frame supporting the same. For insuring exact rolling, the saidroller dies must be exactly adjusted in their positions in order thatthe screw threads of both dies produce exactly corresponding screwthreads on the blank'and further the roller dies must be mounted so thatthey are adapted to be moved under pressure towards each other.

In view of these requirements another object of the improvements is toconstruct the roller dies and bearings so that they permit suchdisplacements, and with'this object in view another feature of ourinvention consists in having one of the bearings of the roller diesfixed in position on the frame of the machine while the blank is beingrolled, while the other roller die is mounted, together with the shaftcarrying the same and the driving gearing, so as to be movable on thesaid frame in a direction transversely of the axis of the roller dies byhydraulic pressure.

To' permit axial displacement of the roller dies the bearing of one ofthe said dies is mounted on the frame of the machine so as to beadjustable longitudinally of the axis of the die.

Another object of the improvements is to mount the bearings of theroller dies so that they may be exactly adjusted with their axesparallel to or angularly of each other, and with this obone of the saidbearings in the manner of a turn table on a vertical pivot bolt the axisof which passes between the said roller dies.

To permit the said movements of the roller dies, the driven shaftscarrying the same are connected with driving shafts disposedperpendicularly to the said driven shafts and parallel to each other,and the said driving shafts are made in telescoping sections permittingthe same to be extended or reduced in length, according to the positionof the driven shaft and its roller die, and in addition the drivingshaft connected with the roller die mounted on the said turn table isconstructed for being yieldable transversely of its axis, in accordancewith the position of the shaft driven thereby.

By connecting parallel driven shafts with parallel driving shafts thegears connecting the driving and driven shafts are displaced withrelation to each other longitudinally of the driving and driven shaftsinstead of being located one beside the other, so that there issuflicient room to provide strong gearings such as are necessary fortransmitting the power from the driving to the driven shafts.

Another object of the improvements is to provide a machine in whichexcessive axial strains on the driving mechanism of the roller dies areprevented, and with this object in view our invention consists inmounting the said roller dies in their bearings so as to be yieldable inaxial direction, the said roller dies-being preferably acted upon bysprings.

Other objects of the improvements will appear from the followingdescription.

For the purpose of explaining the invention an example embodying thesame I has been shown in the accompanying drawings'in which the samereference characters have been used in all the viewsto indicatecorresponding parts. In said drawings:

Fig. 1 is an elevation showing the top part of the machine, 7

Fig. 2 is a plan view of Fig. 1 partly in section,

Fig. 3 is a side elevation of the machine,

Fig. 4 is a sectional elevation taken on the line H of Fig. 2, and

Fig. 5 is an elevation showing a modification of the blank supportingdevice, the blank being shown in section.

In the example shown in the figures the machine comprises a frame I onwhich the operaject in view our invention consists in mounting tiveparts are mounted. The said operative parts comprise a pair of rollerdies 2 and I 10- .to the frame. ed so as to beextensible in accordancewith the cated one beside 'the other and formed about theircircumferences with similar screw threads, shafts 4 and 5 to which thesaid rollerdies are secured, shafts 8 and l perpendicular to. the shafts4 and 5 and connected therewith respectively by worm gearings 8, 9 andII, a pair of gear wheels, l2, [3 connecting the shafts 5 and I, a beltgearing I4; and a motor such as an electromotor. l5 ,for driving themechanism.

- The said electromotor is mounted on'a bracket l8 secured to the frameLand the gear wheels 3 41 operating an electrical contact 48. includedin an electrical circuit controlling the supply of oil,

as will be described hereafter. In lieu of the said cylinder 46 andpiston" a contact may be provided in connection with the pressure gauge45.

The-housing 26- of the shaft 5 is mounted on a plate 55 made, integralwith uprights 56 to P which the housing 26 is secured by means of- I2and I3 are enclosed-within a casing I'I- fixed The shafts 5 and l areconstructadjustment of the bearings of the shafts 4 and 5 to bedescribed hereafter. As shown the said shafts 5 and I consist oftelescoping-sections connected with each other by keys. Further, theshaft 1 is'capable to yield in transverse dimotion, and for this purposeit includes two universal Joints I8 and I9, 2 showing a Hardy joint.Finally the shaft l-comprises a coupling consisting of a pair of flangesconnected by screws 21 passed through circumferential slots made in oneof the said flanges.

The shafts 4 and 5 are mounted in substantially cylindrical housings 25and 26 by means of anti-friction bearings 23 and 21, and the gears 9 andII are mounted on the shafts 4 and 5 so as to permit axial displacementof the'shafts. The zonstruction will be described with reference -to theshaft 4, and it will be understood that-the screws 51, the said screwsbeing passed through slots made in the uprights and permitting adjustment of the housing 26 in the direction of the axis of the shaft 5.The plate 55 is mounted on the'frame I so that it may be turned about avertical pivot bolt 58 fixed to the frame. For

setting the bed plate in position screws 59 are providedwhich are passedthrough lugs 68 risin from the frame I, and which engage the plate 55 atpoints located at opposite sides of the pivot bolt 58. After thussettingthe plate 55 it is fixed in position by means of screws 54.

It appears therefore that the housing capable of movements in twodirections, first of 1 a movement longitudinal of the. axis of the shaft5 and second of rotary movement about the pivot mounting of the shaft 5and the gear II is similar in construction. As shown,.the gear 9- issupported on step bearings 28 and- 29 and it is acted -upon by a, coiledspring 3|! supported on a disk bolt 58. The said axial adjustmentpermits the rolle'rs 2 and 3 to be adjusted relatively to each other sothat the screw-threads formed thereon engage correspondingportions ofthe surface of the blank on which the screw threads are to be producedby rolling, and the rotary movement of the plate 55 permits the rollersto be placed either with their axes exactly parallel for producing screwthreads on cylindrical blanks, or

with their axes at difierent angles for producing 3| fixed to the rearend of the shaft 4. The step bearing 28 is supported on the race ringsof. the

anti-friction bearing 23, and the step bearing 29 is normally supportedon a shoulder 22 formed within the housing 25. Thespring 30 permits theshaft 4 to yield in axial direction in case ofexcessive axial strainbeing exerted by the roller die 2. The gear 9 is connected to the shaft4 by means of a key 32 permitting axial movement of the shaft relativelyto the gear.

The housing 25 is secured to or made integral I with a slide 35 which isguided on the frame I transversely of the axis of the shaft 4 by meansof guide ways 36, and it is adapted to be shifted in transversedirection for exerting rolling pressure on theblank by means of a pairof hydraulic cylinders 31 fixed to an upright 38 rising from the frame Iand containing pistons 39 and piston rods 48 acting on an upright 4|rising from the slide 35. The said cylinders have a supply of oil underpressure, and they are adapted to be retracted, when the supply of oilis interrupted, by means of a spring 42 bearing on the upright 38 andacting on the head 44 of'a screw bolt 34 passed through a hole made inthe upright 38 and fixed to a'block 33 made integralwith the slide 35.The head 44 may be provided with a suitable arm projecting towards theupright 38 and adapted for engaging the same as the slide 35 advances,for limiting the movement of the said slide.

.011 under pressure is supplied to the cylinders 31 through pipes 43 bycontrolling devices which 1 will be described hereafter. Forascertaining the pressure within the cylinders 31a pressure gauge 45 isprovided, and for automatically interrupting the supply of oil to thecylinders an electrical control device may be provided which comprises acylinder 46 containing a spring pressed pistonscrew threads on conicalblanks.

The diiierent adjustments of the shafts 4 and 5 require theadjustability of the shafts 5 and I referred to above, and -it-will beunderstood that the movement of the housing 25 and the shaft] requiresonlyv longitudinal adjustment of the-- shaft 6, While the two differentadjustments of the housing 26 and the shaft 5 require in additionlateral displacement of the outer end of the shaft I, for which purposethe said universal joints l8 and are provided.

Below the roller dies 2 and 3 a supporting member St is provided whichis located with its top face so far belowthe plane passing through theaxes of the said roller dies that the blank being rolled, is locatedwithits axis below the plane. Thus in rolling the dies engage the blanksomewhat above the horizontal plane passing through the axis ,of theblank, and thereby the r blank cannot be ejected from between the diesby the circumferential forces acting thereon. Preferably the saidsupport is rockingly mounted on a bracket 52 secured to the frame I sothat it follows the transverse movement of the right hand roller die 2as rollingof thescrew threads,

thereof, the said arm being adapted to be passed into'the bore ofthetubular blank for supporting the same.

In l we have shown a devicefor measuring the depth of the screw threadsbeing rolled.

The said measuring device comprises a measuring instrument 15 having adial and a hand and mounted at a suitable part of the machine, and atransmission gearing connected with the roller dies. As shown the saidgearing consists of arms 16 and 11 rotatably mounted on disks i8 and I9fixed coaxially to the ends of the roller'dies, a link 80 connecting thesaid arms at their bottom ends, a link 8| connecting the arm 11 with arelatively fixed part 82 of the plate 55, an arm $3 jointed to the arm"il, a link 86 connecting the arm 83 with the arm 16', a spring 85intermediate the said arms 83 and i6 and preventing lost motion'in thejoints of the arms 83 and it, and a rod 86 connecting the arm 83 withthe mechanism of the measuring instrument 35. at the top. end of the arm83 an insulated contact Bl is provided which cooperates with a contactscrew 88 carried by the arm ll, the insulated contact 3? being connectedby a lead as with the electromagnet it.

When the roller die 2 is advanced by the slide 35 towards the roller die3 for rolling the threads on the blank the arm l? is held in position bythe link 8|, while the arm it is turned with its top end to the left,and this movement is transmitted through the link as and the rod 85 tothe measuring instrument 75 which therefore indicates the advance of therolling operation. When the insulated contact 81 makes contact with thescrew 88 the electric circuit of the electromagnet I is closed throughthe lead 89 and through the body of the machine, so that the supply ofoil to the cylinders 37 is interrupted. By means oi' the contact screw88 the apparatus maybe set in accordance with the inner diameter of thescrew threads to be rolled on the blank.

The operation of the machine is as follows:

The blank to be threaded is placed between the roller dies Z and 3, andthe said roller dies are advanced towards each other so as to looselyengage the said blank. The housing 26 is adJusted on the bed plate 55 byloosening the screws 51, shifting the housing on the bed plate axiallyof the roller dies and again fixing the same in position by means of thescrews 51. Exact adjustment of the screw threads relatively to eachother is obtained by disconnecting the disks 20 of the shaft 1 andturning the same relatively to each other, the said rotary movementbeing 7 transmitted through the shaft to the roller die 3. The angularposition of the roller dies is adjusted by loosening-the screws 54 andturning the bed plate 55 about its pivot bolt 58, the bed plate beingfinally fixed in position by means of the screws 54.

After the operative parts of the machine have thus been-adjusted oilunder pressure is admitted to the cylinders 31 by opening the valvecontrolled by the lever 00, the pressure of'the oil within the cylindersI} being gradually increased. Simultaneously the electromotor I5 isswitched in for imparting rotary movement to the roller dies 2 and I. Asthe roller die 2 is advanced towards the die 3 the hand of the messuringinstrument l5 advances, thus showing the advanceof the rollingoperation. .Finally the insulated contact 81 engages the screw contactll. thus energizing the electromagnet Ill and interrupting thetransverse movement of the roller die'2. v

The supply of pressure to the cylinders I! is controlled by means of avalve chest 85 having a supply of oil under pressure through a pipe 6 6'and connected with the aforesaid oil supply pipes 43 to the cylinders31. Within the valve chest a valve is located which is operated by meansof a hand lever 68 and a rod 89; Further, the said valve may be closedindependently of the rod 69 by means of an electromagnet 10 acting on alever ii, the said electromagnet being energized through leads 12including the aforesaid contact 88.

We cl:

1. In a screw threading machine, comprising a pair of roller dies placedone beside the other in position for receiving a blank between the same,shafts on which said roller dies are mounted, common driving means forsaid shafts, and driving connections between said driving means and eachof said shafts, the improvement herein described which consists in aseparable coupling arranged in the connection between the driving meansand one of said shafts, said coupling when disengaged permitting therotation in circumferential adjustment stone of the said roller diesrelatively to the other.

2. In a screw threading machine, comprising a frame, a pair of rollerdies mounted on said frame one beside the other in position forreceiving a blank between the same, and bearings for said roller diesmounted on said frame, the bearings of one of said dies being movabletransversely of the axes of said roller dies, the improvement hereindescribed which consists in hydraulic means for automatically moving thebearings of one of said dies towardthe axial line of the companion dieas the thread-cutting progresses, and for holding the die under pressureto the work throughout the thread-cutting operation, and means forcontrolling the hydraulic pressure acting on said bearing.

3. In a screw threading machine, comprising a frame, a pair of rollerdies placed one beside the other and adapted to receive a blank betweenthe same, bearings for said roller dies, means for forcing the bearingsof the dies severally towards each other, and driving means for saidshafts, the improvement herein described which consists in a tablemounted on said frame and supporting the bearings of one of said dies,said table having pivotal movement about an axis perpendicular to thecommon axial plane of the said dies and passing between the said rollerdies, whereby the position of the table and of the bearings bornethereby may be adjusted, and means for securing said table in adjustedposition on said frame.

4. In a screw-threading machine comprising a pair of roller dies placedone beside the other and adapted to have a blank placed between them.means for rotating said roller dies, and means for forcing said rollerdies toward each other for exerting rolling pressure on said blank, theimprovement herein described which consists in indicating meansconnected with said roller dies and adapted to indicate the distancebetween the axes thereof, the said indicating means being in the form oflinks arranged substantially in the form of a parallelogram, two

opposing links being rotatably mounted on the axis of said roller dies,an arm pivotally mounted on one of said links mounted on said roller 4hydraulic means for forcing said roller diestowards each other forexerting rolling pressure on said blank, a valve controlling thesupplyoi pressure fluid to said hydraulic means, and electrical meanscontrolled by said roller dies adapted to close said valve whentheroller dies have been advanced towards each other to a predetermineddistance. I i

6. In a screw-threading machine that includes a pair of roller diesformed with external screw threads and adapted to receive between them ablank to be threaded, and means for rotating the dies, the improvementherein described that consists in means for holding one of the rotatingdies to engagement upon an introduced blank yieldingly and under threadcutting pressure, and means efiective on the relief of such pressure forretracting said die. I

7. In a screw-threading machine that includes a pair of roller diesformed with external screw threads, arranged in parallelism, and adaptedto receive between them a blank to bethreaded, means for rotating thedies, and means for advanoing one of the dies toward the other asoperjation progresses, the improvement that cohsists in a supportadapted to hold a blank to position to be operated upon by said dies,the support being movable in a directiontransverse to the axes of theroller dies.-v

8. In a screw-threading machine that includes tal base-plate, a slidemounted upon said baseherein described which consists of two home by thebearings severally of the two a pair of roller dies formed with externalscrew threads, arranged in parallelism, and adapted to receive betweenthem a blank to be threaded, means for rotating the dies, and means foradvancingone of thedies toward the other as operation progresses, theimprovement that consists in a support adapted to hold a blankto-position to be operated on by-said dies, the support being pivotallymounted on an axis parallel to the axes of the roller dies. v

19, Ina screw-threading machine that includes a ipair of roller diesformed with external screw threads, arranged in parallelism, and adaptedto' thereby, and means for advancing the said slid plate, a housingborne by the slide, a threaded die rotatably mounted on a horizontalaxis in the housing, a plate borne by said base-plate and rotatable upona vertical axis, a housing mounted upon said rotatable plate and athreaded die rotatably mounted on a horizontal axis in the ofsaidrotatableplate, the. housing mounted upon said rotatable plate beingadjustable in the direction of the axial extent of the die borne andholding the die borne thereby yielly under pressure .to engagement withablattroduced between the said die and its compare ion die. v

11. In a screw-threading machine pair of roller dies mounte in t V atmeans for causing the dies togethe with their several ,bearings toadvance one relatively to the other under pressure upon ablankintroduced between them, as, in the course oi operation they sink athread in the blank, the improvement inclu 1'. a dies and radiallyextending from the bearings with reference to the axes of die rotation,link con nection between the two arms, whereby relative movement of thebearings oi the two dies efiects variation in the angular positions ofthe a relatively one to the other, and a measuring de vice responsive tovariation in such angular positions of the two said arms.

12. In a screw-threading machine comprising a pairof roller dies placedone beside the other and adapted to receive a blank between the same,bearings for said roller dies, and driving means for said roller dies,and means for forcing said roller dies towards each other, theimprovement herein described which consists in a pair of housings onefor each die within which the dies are severally mounted for movementboth rotatively and longitudinally in axial direction, and the drivingmeans including a gear borne by the die and supported on va-step bearingwithin the.

housing and restrained thereby from movement in the direction ofthe-axis of the die, the die and the gear being relatively movablein-the di-

